1. Field of the Invention
The invention relates to a wood-impregnating agent as well as the process for its use, especially for the impregnation of wood to be worked mechanically, such as pencil wood for writing, drawing, marking and/or painting pencils of every kind that can be sharpened, and the objects made therewith.
2. Description of Related Art
Wood impregnating agents as well the process for their use for impregnation are fundamentally known. Thus, in claim 1 of German Patent DE-OS 4313219 A1 a process is proposed for the impregnation of wood, seeking chiefly to obtain water-repelling properties by the use of polysiloxanes.
This process is not suitable for the treatment of pencil wood if for no other reason than that it raises toxicological problems. This also applies to the process proposed in claim 2 of European Patent 0393306 B1.
Claim 3 of European Patent 0510435 B1 provides for a process for wood impregnation which starts out from tar oils. The impregnating agents must first be brought to suitable viscosity by temperature. The same is also true of the process described in claim 4 of German Patent 4224510 C1.
The objective of all these known impregnating agents is especially to improve resistance to weathering and fungi. None of these publications discloses the treatment of wood to be specially worked mechanically, especially pencil wood, not to mention an improvement of their mechanical workability.
In claim 5 of European Patent 0596295 A1 a stain is proposed for the blackening of wood. This stain does refer to pencil wood, but it is aimed pre-eminently at a desired staining.
As according to claim 6 of European Patent 0553407 B1, here too acid azo dyes are proposed for wood staining, in suitable mixture which, as every colorist knows, leads to black. The stain proceeds from an improved penetrability, an effect that is achieved solely by the use of surface-active agents, known as wetting agents, by lowering surface tension.
If one wishes to impregnate relatively large sizes of wood, e.g., such as those that require more than 5 mm depth of penetration, the lowering of surface tension is no longer sufficient.
Moreover, the effectiveness in other types of wood can only be achieved by uneconomical impregnation times. Furthermore, the paraffin dispersion produces an insufficient gliding and lubricating effect for heavy-duty machines and tools.
European Patent 0695608 (claim 7) proposes a stain and a process for the dyeing of wood which is essentially based on the known teaching of wood dyeing which is intended to prevent discoloration by buffering of the pH value and the complexation of undesirable ions.
As already mentioned in carefully considering European Patent 0596295 A1 (claim 5), the improved penetrability postulated is not effective at comparatively great depths of penetration. With the introduction of buffer substances which set the pH &gt;7 and the use of complexing agents, any substantivity of ionogenic compounds is destroyed. Here improvement of the workability can be expected only with small wood sizes and with already readily workable wood, such as incense cedar or jelutong.
German Patent 3911091 C2 (claim 8) describes an aqueous impregnation solution which, besides inorganic salts, such as silicates, borates, carbonates and/or phosphates, also provides waxes and amines. The purpose in so doing is to bind the acids as well as the formaldehyde contained in the wood, so that when it is used for packing wood it does not cause any corrosion of the packaged products. Moreover, this seeks to provide hydrophobicity. Improvement of workability can not be achieved thereby.
By comparison, the object of the invention is to create an impregnating agent or an impregnating dispersion and/or emulsion for wood which penetrates deeply into the wood and/or improves the mechanical workability of the wood in such a way, for example, that even with fast machines no burn spots occur and the surface is not frayed.
The impregnated wood should not be impaired therewith and/or thereby in either its glue-bonding ability or its varnishing ability. Furthermore, even wood that is difficult to work or poorly sharpenable should still have the described advantages after its impregnation.